Hormoceras confluens Kützing, 1842: 734 (type locality: Split, Croatia).
Ceramium circinatum (Kützing) J. Agardh var. confluens (Kützing) Ardissone, 1883: 112.
Taxonomic synonym:
Hormoceras decurrens Kützing, 1842: 733 (type locality: Split, Croatia).—Dickie, 1874b: 197.
INDIAN OCEAN DISTRIBUTION: Mauritius.
Note: The synonymy was proposed by Ardissone (l.c.).